Traditionally, a thesis or dissertation comprises a unified body of work. The chapters are like chapters of a book or monograph–each tells part of a single story.
But these days it’s fairly common for a thesis or dissertation in ecology (and probably many other scientific fields) to comprise multiple projects that are only loosely related. My own dissertation comprised two chapters that were part of one integrated project,* and a third chapter that was originally a side project.** I still wrote “bookend” chapters that presented the whole thing as an integrated body of work, and my supervisor and committee were fine with it.*** But honestly, I didn’t see my dissertation that way, and still don’t. Don’t get me wrong, I think it was a useful exercise to have to write the bookends. They forced me to think about the big picture of my developing “research program” and identify the common threads that tie together all the work that I do. But a research program comprising separate projects linked by common threads isn’t nearly as unified as a traditional dissertation. And so those bookend chapters felt like a bit of a fib.
Can a thesis or dissertation comprise multiple unrelated projects? I ask because, once you’re prepared to allow theses and dissertations that are “unified” only in the sense that mine was, it’s not clear where you stop or why. If all you need is some sort of common thread, well, those aren’t that difficult to come up with. For instance, Meg’s talked about how for a while she had two totally separate projects going, which she called “thesis 1” and “thesis 2”. But had she wanted to, and had her committee been ok with it, I’m sure she could’ve written them both up as a single thesis, unified only in the sense that mine was. Heck, they were both about Daphnia, it wouldn’t have been that hard.
To be clear, I and most everyone whose views I know is fine with theses that are only unified in the loose sense that mine was. But I can imagine that not everyone is fine with this, feeling that something important is lost if a student can get a graduate degree without ever producing a large, tightly-integrated body of work. So as a conversation starter, here’s a little poll:
Looking forward to your comments.
p.s. After I wrote the above, it occurred to me that even if a thesis doesn’t necessarily have to be a single tightly-integrated project, arguably the proposal should still be for a single tightly-integrated project. That was the case for me, and for every case I know of. There’s a lot of value in being forced to develop a proposal for a master’s or PhD’s worth of tightly-integrated work. Even if you later end up writing a loosely-integrated thesis that’s somewhat different than what you proposed, because s**t happens.
*Those chapters eventually became Fox 2002 and Fox 2007. See if you can guess what Fox 2007 was originally about! (I ended up having to reframe it to address a completely different question in order to get it published.)
**That became Fox and Morin 2001.
***I wrote that my dissertation was about “causes and consequences of community structure”. The first two, tightly-integrated chapters were about the causes, and the third chapter was about the consequences. The “causes and consequences” framing let me present it as an integrated body of work.